Why are per diem rate increases problematic for researchers?

• A. The investigators would have to reduce the number of animals they use so there is no net increase in charges.
• B. NIH prohibits changing a per diem rate once a grant has been awarded.
• C. Investigators would require shorter conditioning periods so they aren't be charged for as many days.
• D. Per diems are often paid from fixed grants that were based on the previous rates.

Answer: (D)

Per diem costs are the daily charges used to cover animal care and related facilities within a grant budget. When a grant is awarded, the total funds and the budget are usually set using the per diem rate in effect at that time. If per diem rates increase, the actual daily costs become higher, but the grant’s total funding is often fixed and based on the old rates. That mismatch means the grant may no longer fully cover the day-to-day animal care expenses, creating a budgeting shortfall. Researchers may need to seek budget amendments or additional funds, or otherwise absorb the extra costs, which makes rate increases problematic.